Field of the Disclosure
The present disclosure is directed to methods for making monolithic polar crystals and more specifically to top-seed solution growing polar, noncentrosymmetric crystals.
Background
There is a demand for rechargeable batteries with properties that include compact size, high-energy density, environmentally friendly materials, and at a lower cost relative to the current batteries. These demands have contributed to the development of lithium-ion batteries and lithium-ion technologies. Generally, a lithium-ion battery contains an anode, an electrolyte solution (the separator), and a cathode. The anode, or negative electrode, in a lithium-ion battery is conventionally composed of graphite coated on a copper foil. Graphite is a highly conductive and layered material used as the active material in the anode because it can reversibly intercalate lithium ions between its layers. The separator has the role of separating the cathode from the anode. In the charging cycle the positively charged lithium ions move from the cathode to the anode, through the separator via an electrolyte solution. Likewise during the battery discharge process the lithium ions migrate in the opposite direction from the anode to the cathode passing through the separator. Within the battery industry, the lithium-ion battery anodes and electrolyte solutions are considered established and optimized technologies, thus continued development has shifted to other battery components.
More specifically, the lithium containing material in the anode is the focus of industrial research and development. As such, a number of lithium anode materials have been developed and implemented in batteries, including LiCoO2, LiMn2O4, and LiFePO4. However, these materials are implemented as micron-sized particulates, grains, or powders, and the lithium cation (Li+) Li+ leaves the powder in order to provide the ion migration between the anode and the cathode. The particulates inherently include grain boundaries that limit ion migration, increase the voltages necessary for ion migration, and decrease the ion densities in the battery. Thus, there is an increased demand for anodic materials with increased particulate size and ion density with decreased grain boundary ion limitations and decreased voltage requirements. Thus, the present disclosure relates to macroscopic ionic materials.